Merge PR #470 - implement automatic DST toggling

Merge PR #470 - implement automatic DST toggling

Implements logic to automatically offset daylight saving time settings
when calculating timezone offsets. This should make the DST functions
work automatically with no need for user input in most cases.

Reviewed-by: Matheus Afonso Martins Moreira <matheus@matheusmoreira.com>
GitHub-Pull-Request: https://github.com/joeycastillo/Sensor-Watch/pull/470